Visceral fat meter provided with tonometer

ABSTRACT

A visceral fat scale equipped with a sphygmomanometer is described, with which a subject can keep track of blood pressure values and grasp the state of obesity to attain more accurate, comprehensive and diversified diagnoses and disease prevention. The visceral fat scale is designed such that after exerting pressure to an artery of a subject by inflation of a cuff, a pulse wave signal is detected in the course of gradual cuff deflation and blood pressure is obtained based on the detected pulse wave signal. The scale comprises an increment/decrement key and display mode selector key for inputting personal data of the subject; an arithmetic operation unit for calculating the amount of visceral fat of the subject based on data input by these keys; and a display unit for displaying a result of the calculation performed by the arithmetic operation unit.

TECHNICAL FIELD

[0001] The present invention relates to a visceral fat scale equippedwith a sphygmomanometer, which is capable of making simultaneousmeasurements of blood pressure and percent body fat.

BACKGROUND ART

[0002] The latest studies have thrown considerable light upon therelationship between hypertension and various diseases. People, who aregenerally diagnosed as having hypertension, with a systolic bloodpressure of 140 mmHg or more and a diastolic blood pressure of 90 mmHgor more, commonly develop cerebral hemorrhage and cerebral infarction.In view of this, the importance of health care has been furtheremphasized in order to prevent diseases caused by high blood pressure.For effective prevention of hypertension, not only periodic medicalcheck-ups such as blood pressure taking but also awareness of thecondition of blood pressure on a daily basis become necessary.

[0003] Recently, simplified sphygmomanometers which enable easymeasurements of blood pressure on a daily basis are commerciallyavailable so that continuous, easy personal blood pressure controlbecomes possible. For such simplified sphygmomanometers, the so-calledoscillometric method (pressure pulse wave oscillation method) isprevailing which is distinguished from the Korotcoff method that hasbeen conventionally used as the stethoscopy in the medical field andothers. The oscillometric method is carried out in such a manner that acuff (arm wrap) is worn around fingers, a wrist or an upper arm; air issent to the cuff to press an artery; pressure in the cuff is graduallyreleased to detect pulse wave components with a pressure sensor; andblood pressure (systolic and diastolic blood pressures) is measuredbased on the detected pulse wave components.

[0004] A known electronic sphygmomanometer utilizing the oscillometricmethod is designed as follows: For setting of a target inflation valuefor the cuff, a cuff pressure signal is detected, for example, duringinflation of the cuff. Then, a systolic blood pressure (e.g., a cuffpressure corresponding to one-half the maximum amplitude of the pulsewave) is simply estimated from the maximum amplitude value of the pulsewave included in the signal, and a value obtained by adding a specifiedvalue to the estimated systolic blood pressure is automatically set as atarget inflation value. In this case, for the purpose of reducing thetime required for a blood pressure measurement as well as the pain givento the person under measurement, the rising speed of pressure at thetime of cuff inflation is set to a higher value than the speed of cuffdeflation during which a measurement of systolic and diastolic pressuresis made.

[0005] In the medical field, there have recently been advances in thestudies of the association between hypertension and obesity and it hasbeen found that obesity is not simply a state of overweight and thedistribution of body fat bears relevance to blood pressure. It has beenfurther reported that the distribution of abdominal body fat (visceralfat type obesity) deeply concerns hypertension.

[0006] In addition to BMI (Body Mass Index=body weight/(body height)²)that is widely used as an index indicative of the degree of obesity,various indices (e.g., percent body fat, the cross-sectional area ofabdominal visceral fat, etc.) to an assessment of visceral fat typeobesity have been devised and respectively proved to be useful in theclinical sites. Of these indices, percent body fat is obtained based onpersonal specific data on the subject such as height, weight, age andsex and based on the measurement of body impedance. The cross sectionalarea of abdominal visceral fat is obtained from a CT scan of the abdomenof the subject around his umbilicus and from estimation based on data onthe waist size of the subject obtained by measuring the abdomen of thesubject around his umbilicus as well as the personal specific datadescribed above.

[0007] The above-described conventional sphygmomanometer has, however,revealed such a drawback that since it measures and deals with bloodpressure alone, it cannot provide more accurate diagnosis ofhypertension taking account of the relationship with the aforesaidvisceral fat type obesity.

[0008] In addition, the conventional sphygmomanometer of this typepresents another problem when setting a target inflation value for thecuff. Specifically, since the conventional sphygmomanometer issusceptible to the influence of noise caused by the fluctuation of acuff pressure signal occurring just after cuff inflation, the detectionof a pulse wave at the time of cuff inflation cannot be always carriedout correctly, so that an estimated value of systolic blood pressureand, in consequence, a target inflation value based on the estimatedvalue become wrong. Especially, if the target inflation value is set toan abnormally low value, there will occur an error in the latermeasurement of blood pressure values (i.e., systolic blood pressure anddiastolic blood pressure) at the time of cuff deflation due to a lack ofinflation.

[0009] The present invention has been directed to overcoming theforegoing shortcomings and a primary object of the invention istherefore to provide a visceral fat scale equipped with asphygmomanometer with which a subject can keep track of his bloodpressure values and grasp the state of obesity to realize more accurate,comprehensive and diversified diagnoses and disease prevention. Anotherobject of the invention is to provide a visceral fat scale equipped witha sphygmomanometer wherein even if it fails in making an accuratemeasurement of the maximum amplitude value of a pulse wave at the timeof cuff inflation, an error will not occur in the measurement of bloodpressure values at the time of cuff deflation.

DISCLOSURE OF THE INVENTION

[0010] The above objects can be accomplished by a visceral fat scaleequipped with a sphygmomanometer according to a first aspect of theinvention, wherein after exerting pressure to an artery of a subject byinflation of a cuff, a pulse wave signal is detected in the course ofgradual cuff deflation and blood pressure is obtained based on thedetected pulse wave signal, the visceral fat scale comprising:

[0011] an input device for inputting personal data of the subject;

[0012] an arithmetic operation unit for calculating the amount ofvisceral fat of the subject based on the data input by the input device;and

[0013] a display unit for displaying a result of the calculationperformed by the arithmetic operation unit.

[0014] According to the invention, since the amount of visceral fat of asubject is calculated by the arithmetic operation unit based on personaldata input by the input device and the result of the calculation isdisplayed on the display unit, the subject can keep track of his bloodpressure values and grasp the amount of visceral fat, in other words,the state of obesity, so that control of blood pressure in connectionwith visceral fat type obesity becomes possible. This enables moreaccurate, comprehensive, diversified diagnoses and disease preventionwith a simplified device, compared to the conventional health managementbased on blood pressure alone.

[0015] Preferably, in the invention, the personal data input by theinput device includes the height, weight and waist size of the subject,and the arithmetic operation unit calculates the BMI of the subject inaddition to the amount of visceral fat of the subject based on the datainput by the input device. This makes it possible to calculate not onlythe amount of visceral fat but also BMI (Body Mass Index) that isinternationally used as an index to an assessment of obesity/emaciation,so that more reliable data on the state of obesity can be attained.

[0016] In this case, the display unit preferably displays the ranks ofthe visceral fat amount and BMI of the subject, these indicesrespectively having a plurality of ranks. By representing the degree ofobesity according to the ranks of the indices, the subject can moreeasily make a self assessment of the degree of obesity.

[0017] Preferably, the arithmetic operation unit makes an assessment ofobesity by comparing the visceral fat amount and BMI of the subject withtheir respective reference values for assessment which have been inputbeforehand, and wherein the display unit displays a result of theassessment of obesity.

[0018] The display unit preferably displays blood pressure values andthe amount of visceral fat at the same time. This allows the subject tograsp his blood pressure values and the state of obesity on a firstviewing of the display unit.

[0019] In addition, it is preferable that the arithmetic operation unitcalculate the amount of change from a previous measurement result andthe ratio of the present measurement result to the previous measurementresult for the blood pressure values and visceral fat amount of thesubject, and that the display unit display a result of the calculation.With this arrangement, the subject can more accurately grasp his stateof health through the relationship between the degree of change in hisblood pressure and the degree of change in the amount of visceral fat ofhis own, so that he can utilize the acquisition for proper health careand disease prevention.

[0020] The amount of visceral fat may be the cross-sectional area ofabdominal visceral fat of the subject which is used as an index to anassessment of obesity in the clinical site. Herein, the target cuffinflation value may be determined by a systolic blood pressure estimatedbased on a pulse wave generated during cuff inflation and by thecross-sectional area of abdominal visceral fat. Alternatively, thetarget cuff inflation value may be determined by a systolic bloodpressure estimated based on a pulse wave generated during cuff inflationand by a result of an assessment of obesity. With this arrangement, evenif the maximum amplitude value of a pulse wave generated during cuffinflation cannot be correctly measured, there will not occur such anunfavorable situation that blood pressure values (systolic bloodpressure and diastolic blood pressure) to be measured at the time ofcuff deflation become incorrect owing to a lack of inflation.

[0021] According to a second aspect of the invention, there is provideda visceral fat scale equipped with a sphygmomanometer, wherein afterexerting pressure to an artery of a subject by inflation of a cuff, apulse wave signal is detected in the course of gradual cuff deflationand blood pressure is obtained based on the detected pulse wave signal,the visceral fat scale comprising:

[0022] an input device for inputting personal data including the height,weight and waist size of the subject;

[0023] electrodes for current application and electrodes for measurementwhich are brought into contact with part of the body of the subject;

[0024] a body impedance measuring unit for measuring the body impedanceof the subject based on a signal from the measurement electrodes;

[0025] an arithmetic operation unit for calculating at least any of theBMI, percent body fat and visceral fat amount of the subject based ondata input by the body impedance measuring unit and data input by theinput device; and

[0026] a display unit for displaying a result of the calculationperformed by the arithmetic operation unit.

[0027] In addition to the first aspect, the invention has the featurethat the body impedance of the subject is measured and, based on thismeasurement, the percent body fat of the subject is calculated anddisplayed. Therefore, the subject can more accurately grasp not only hisblood pressure values but also the state of obesity and, accordingly,the effect of the first aspect is enhanced.

[0028] Preferably, in the invention, the display unit displays the rankof any of the BMI, percent body fat and visceral fat amount of thesubject, each of these indices having a plurality of ranks. With thisarrangement, the subject can more easily make an assessment of thedegree of obesity of his own.

[0029] Preferably, the arithmetic operation unit makes an assessment ofobesity by comparing any of the BMI, percent body fat and visceral fatamount of the subject with their respective values for assessment whichhave been input beforehand, and the display unit displays a result ofthe assessment of obesity.

[0030] The display unit preferably displays blood pressure values andthe amount of visceral fat at the same time. This allows the subject tograsp his blood pressure values and the state of obesity on a firstviewing of the display unit.

[0031] In addition, it is preferable that the arithmetic operation unitcalculate the amount of change from a previous measurement result andthe ratio of the present measurement result to the previous measurementresult for the blood pressure values and visceral fat amount of thesubject, and that the display unit display a result of the calculation.

[0032] The amount of visceral fat may be the cross-sectional area ofabdominal visceral fat of the subject which is used as an index to anassessment of obesity in the clinical site. Herein, the target cuffinflation value may be determined by a systolic blood pressure estimatedbased on a pulse wave generated during cuff inflation and by thecross-sectional area of abdominal visceral fat. Alternatively, thetarget cuff inflation value may be determined by a systolic bloodpressure estimated based on a pulse wave generated during cuff inflationand by a result of the assessment of obesity.

BRIEF DESCRIPTION OF THE DRAWINGS

[0033]FIG. 1 is a general perspective view of a visceral fat scaleequipped with a sphygmomanometer according to a first embodiment of theinvention.

[0034]FIG. 2 is a block diagram of the visceral fat scale equipped witha sphygmomanometer according to the first embodiment.

[0035]FIG. 3 is a flow chart (the first stage) of the operation of thevisceral fat scale equipped with a sphygmomanometer according to thefirst embodiment.

[0036]FIG. 4 is a flow chart (the second stage) of the operation of thevisceral fat scale equipped with a sphygmomanometer according to thefirst embodiment.

[0037] FIGS. 5(a) and 5(b) are explanatory graphs showing a bloodpressure measuring method according to the first embodiment.

[0038]FIG. 6 is a general perspective view of a visceral fat scaleequipped with a sphygmomanometer according to a second embodiment.

[0039]FIG. 7 is a block diagram of the visceral fat scale equipped witha sphygmomanometer according to the second embodiment.

[0040]FIG. 8 is a flow chart (the first stage) of the operation of thevisceral fat scale equipped with a sphygmomanometer according to thesecond embodiment.

[0041]FIG. 9 is a flow chart (the second stage) of the operation of thevisceral fat scale equipped with a sphygmomanometer according to thesecond embodiment.

BEST MODE FOR CARRYING OUT THE INVENTION

[0042] Referring now to the accompanying drawings, there will bedescribed preferred embodiments of a visceral fat scale equipped with asphygmomanometer according to the invention.

[0043]FIGS. 1 and 2 show a general perspective view and block diagram,respectively, of a visceral fat scale equipped with a sphygmomanometeraccording to a first embodiment of the invention.

[0044] The visceral fat scale equipped with a sphygmomanometer 1 of thisembodiment is designed to measure blood pressure, using the so-calledoscillometric blood pressure measuring method (the pressure pulse waveoscillation method) and has as main components, a machine body 2 and acuff (arm wrap) 4 which is connected to the machine body 2 through anair tube 3 and wearable around an arm of a subject. Disposed within themachine body 2 is an air supply unit 5 which is connected to the airtube 3 and comprised of a pump for supplying the cuff 4 with air and apressure release valve for releasing the air pressure of the cuff 4, andothers. An air pressure sensor 6 is also disposed within the machinebody 2, for detecting pulse wave components through detection of the airpressure of the cuff 4. The air supply unit 5 and the air pressuresensor 6 are connected to a central processing unit (arithmeticoperation unit) 8 through an I/O circuit 7.

[0045] The machine body 2 has, at its top face thereof, a display unit 9and input keys/switches 14 which are comprised of a power switch 10, ablood pressure measurement starting switch 11, an increment/decrementkey 12, and a display mode selector key 13. Further, the centralprocessing unit 8 is provided with a memory 15 for storing data such aspersonal data which has been input by the input keys/switches 14 andsent to the memory 15 through the I/O circuit 7. It should be noted thatthe increment/decrement key 12 and the display mode selector key 13correspond to the input device of the present invention.

[0046] Reference is made to the flow charts of FIGS. 3 and 4 to describethe operation of the visceral fat scale equipped with a sphygmomanometer1 having the above structure. Note that code S stands for a step.

[0047] S1: The power switch 10 is turned ON to put the machine body 2into operation.

[0048] S2: The display mode selector key 13 and the increment/decrementkey 12 are operated thereby selectively inputting the personal data ofthe subject such as height, weight and waist size. The data thus inputis stored in the memory 15.

[0049] S3: Based on the personal data stored in the memory 15, thecentral processing unit 8 calculates the BMI and abdominal visceral fatcross-sectional area (AV) of the subject and the results of thecalculations are stored in the memory 15. The arithmetic expressionsused for the above calculations have been stored in the memory 15beforehand and are called into the central processing unit 8 whenexecuting the arithmetic operations. As the simplest expression forobtaining abdominal visceral fat cross-sectional area (AV), thefollowing regression equation (1) is used:

AV=a1×W _(L) +d ₁  (1)

[0050] where W_(L) is waist size. The coefficient a₁ and constant d₁ ofthis expression are derived from a statistic technique such asregression analysis, based on the correlation between the waist size andabdominal cross-section C/T data of a selected group of subjects.

[0051] S4: The BMI and abdominal visceral fat cross-sectional area (AV)which have been calculated and stored in the memory 15 at step S3 arecompared to their reference values set for the obesity assessment. Therank of obesity for the subject is determined and stored in the memory15. The reference values and arithmetic expression used for thecomparison have been stored in the memory 15 and are called into thecentral processing unit 8 when executing the arithmetic operations. Asthe reference values for the obesity assessment, BMI=25 (for male andfemale) and abdominal visceral fat cross-sectional area (AV)=100 cm²(for male and female) are used. It should be noted that BMI isinternationally used as an index to an assessment of obesity/emaciationand abdominal visceral fat cross-sectional area (AV) represents theamount of distributed visceral fat and is used for diagnoses of obesityin the clinical site. Obesity is ranked according to these indices BMIand AV. More concretely, BMI is classified as follows: the range of 25to 30 is rank I, the range of 30 to 35 is rank II and the range of morethan 35 is rank III. Abdominal visceral fat cross-sectional area (AV) isclassified as follows: the range of 100 to 125 cm² is rank I, the rangeof 125 to 150 cm² is rank II and the range of more than 150 cm² is rankIII.

[0052] S5: Subsequently, the cuff 4 is worn around an arm of the subjectfor blood pressure measurement.

[0053] S6: The blood pressure measurement starting switch 11 isdepressed, thereby starting blood pressure measurement.

[0054] S7: The air supply unit 5 supplies the cuff 4 with air so thatthe cuff 4 is inflated.

[0055] S8: The pressure of the cuff 4 is detected by the air pressuresensor 6 while the cuff 4 being inflated and a pulse wave to besuperimposed on a pressure signal is detected in the course of theinflation of the cuff 4. The maximum value Amax′ of the amplitude of thepulse wave is obtained to be stored in the memory 15 (See FIG. 5).

[0056] S9: To estimate a systolic blood pressure P₁′ from the maximumamplitude value Amax′ of the pulse wave, an amplitude value A₁′, forexample, is obtained which is one α-th (1/α) the maximum amplitude valueAmax′ of the pulse wave, in other words, which is derived from thefollowing equation:

A ₁′=1/α×Amax′  (2)

[0057] S10: Then, the cuff pressure (estimated systolic blood pressure)P₁′ corresponding to the amplitude value A₁′ obtained at step S9 isobtained and stored in the memory 15.

[0058] S11: To determine a target cuff inflation value based on theestimated systolic blood pressure P₁′, the estimated systolic bloodpressure P₁′ is compared to a specified value (which is, herein, 100mmHg).

[0059] S12: If the estimated systolic blood pressure P₁′ is less than100 mmHg, a check is made to determine whether or not each index (BMIand AV) exceeds its reference value, in other words, whether BMI>25 andAV>100 cm² hold. This check is made in order to determine a target cuffinflation value P_(k) as security for errors in the measurement andestimation, based on the result of the assessment of obesity with thestored obesity indices (BMI and AV).

[0060] S13: If obesity is diagnosed based on the judgement with theindices (BMI and AV), in other words, if BMI>25 and AV>100 cm² hold, thetarget cuff inflation value P_(k) is determined from the equation (3):

Pk=140 mmHg+20×β  (3)

[0061] where β represents a value looked up in Table 1 with an obesityrank I, II or III. TABLE 1 OBESITY RANK I II III BMI β = 1 β = 1.5 β = 2AV β = 1 β = 2   β = 3

[0062] Since the determining factor for the target cuff inflation valueP_(k) thus takes account of the result of the obesity assessment, therewill not occur such an undesirable situation that blood pressure values(i.e., systolic blood pressure and diastolic blood pressure) areincorrectly measured during later cuff deflation, even if themeasurement of the maximum amplitude value Amax′ of the pulse wavegenerated during cuff inflation is not correctly made owing toinsufficient inflation.

[0063] S14: If at least either index BMI or AV does not indicate obesityin the judgement of Step S12, the target cuff inflation value P_(k) isdetermined by the following equation (4):

Pk=140 mmHg (4)

[0064] In this way, the estimated systolic blood pressure P₁′ iscompared to the specified value (100 mmHg) based on the measurement ofthe maximum amplitude value Amax′ of the pulse wave generated duringcuff inflation, and if it is determined that the estimated value P₁′ isless than the specified value and obesity is not diagnosed in theobesity assessment, the target cuff inflation value P_(k) is set to thelowest limit value (e.g., 140 mmHg). With this arrangement, if an erroroccurs in the measurement of the maximum amplitude value Amax′ and inthe calculation of the estimated systolic blood pressure P₁′, the targetcuff inflation value P_(k) will be set to its lowest limit value so thatoccurrence of an undesirable situation can be avoided in which themeasurement of blood pressure values (i.e., systolic blood pressure anddiastolic blood pressure) is incorrectly made during later cuffdeflation.

[0065] S15: If it is judged at step S11 that the estimated systolicblood pressure P₁′ is 100 mmHg or more, a check is then made similarlyto the step S12 to determine whether each of the indices (BMI and AV)exceeds its reference value for the obesity assessment, in other words,whether BMI>25 and AV>100 cm² hold.

[0066] S16: If at least either of the indices BMI and AV does notindicate obesity, the target cuff inflation value P_(k) is determined bythe following equation (5):

P_(k)=P₁′+40 mmHg (5)

[0067] S17: On the other hand, if both indices BMI and AV indicateobesity, in other words, if BMI>25 and AV>100 cm² hold, the target cuffinflation value P_(k) is determined by the following equation (6):

P _(k) =P ₁′+20×β+30  (6)

[0068] S18: After the target cuff inflation value P_(k) has beendetermined in the above-described manner, cuff inflation is carried outuntil the cuff pressure reaches the target cuff inflation value Pk andthen stopped.

[0069] S19: After it is judged that the cuff inflation has stopped, thevalve of the air supply unit 5 is switched to the evacuation side sothat extremely slow deflation of the cuff 4 starts.

[0070] S20: A pulse wave to be superimposed on a pressure signal in thecuff deflation phase is detected and the maximum amplitude value Amax ofthe pulse wave is obtained and stored. Then, in order to estimate asystolic blood pressure P₁ from the maximum amplitude value Amax of thepulse wave, an amplitude value A1 which is one α-th (1/α) the maximumamplitude value Amax′ of the pulse wave, for example, is obtained, inother words, the amplitude value A1 is obtained from the followingequation (7):

A1=1/α×Amax  (7)

[0071] To estimate a diastolic blood pressure P₂ from the maximumamplitude Amax of the pulse wave, an amplitude value A₂ which is oneγ-th (1/γ) the maximum amplitude value Amax′ of the pulse wave, forexample, is obtained, in other words, the amplitude value A₂ is obtainedfrom the following equation (8):

A1=1/γ×Amax  (8)

[0072] The value of 1/α may be 0.5, whereas the value of 1/γ may be 0.7.In place of 1/α and 1/γ, an estimate equation or the like which providesmore improved estimation accuracy may be used.

[0073] S21: After completion of the measurement of systolic bloodpressure and diastolic blood pressure, the evacuation of the cuff 4 isdone by rapid deflation within a short time and then, the deflation ofthe cuff 4 is stopped.

[0074] S22: The blood pressure measurement is completed.

[0075] S23: After completion of the measurement, the display unit 9performs selective displaying of the input data such as the personaldata (height, weight, sex, age, waist size), the blood pressuremeasurements (systolic blood pressure and diastolic blood pressure), theindices (BMI and abdominal visceral cross-sectional area) used for theobesity assessment, the result of the assessment, and the degree ofobesity (the rank of each index).

[0076] The visceral fat scale equipped with a sphygmomanometer 1 of thisembodiment may be designed such that data on blood pressuremeasurements, BMI and abdominal visceral cross-sectional area is storedeach time a measurement is made and each data piece is displayed withthe amount of change from the result of the previous measurement. Inaddition, the scale 1 may display the ratio of the present measurementresult to the previous measurement result (or the ratio of the changebetween the present and previous measurement results to the previousmeasurement result) in terms of blood pressure values and abdominalvisceral cross-sectional area. This makes it possible to get an idea ofthe relationship between the amount of change and the aforesaid ratiowith respect to the amount of distributed abdominal visceral fat andblood pressure values, and therefore, health condition can be moreaccurately grasped based on these values to achieve more adequate healthcontrol. Additionally, changes in each data item may be recordedaccording to a systematic schedule of blood pressure measurements,thereby observing the long-term transition of data and making use of itas a guideline for diagnosis.

[0077]FIGS. 6 and 7 show a general perspective view and block diagram,respectively, of a visceral fat scale equipped with a sphygmomanometeraccording to a second embodiment of the invention.

[0078] The visceral fat scale equipped with a sphygmomanometer 1A of thesecond embodiment has the function of measuring body impedance to obtainthe percent body fat of the subject in addition to the same function asthat of the visceral fat scale equipped with a sphygmomanometer 1 of thefirst embodiment. The parts identical to those of the first embodimentare indicated with the same reference numerals as in the firstembodiment and a detailed explanation of them will be omitted herein.

[0079] The visceral fat scale equipped with a sphygmomanometer 1A of thesecond embodiment has electrodes 16 which are positioned at the frontand back faces of the upper right and upper left ends of a machine body2A and the fingers (e.g., a thumb and an index finger) of both hands ofthe subject touch the electrodes 16. By pinching each electrode 16 withthe fingers of each hand, the body impedance between the fingers of thehand is measured by a body impedance measuring circuit 17, and themeasurement data is input to the central processing unit 8 through theI/O circuit 7 and stored in the memory 15. Based on the measurementdata, percent body fat is calculated. On the upper face of the machinebody 2A, a percent body fat measurement starting switch 18 is providedin addition to the same input keys/switches as in the first embodiment.Herein, each electrode 16 is comprised of, for instance, an electrodefor measurement disposed on the front face of the machine body 2A and anelectrode for current application disposed on the back face of the same.Reference numeral 19 of FIG. 6 designates a stand for setting themachine body 2A up.

[0080] Next, the operation of the visceral fat scale equipped with asphygmomanometer 1A of the second embodiment will be described withreference to the flow charts of FIGS. 8 and 9. It should be noted thatcode T stands for a step.

[0081] T1: The power switch 10 is turned ON to put the machine body 2into operation.

[0082] T2: By depressing the display mode selector key 13 and theincrement/decrement key 12, the personal data of the subject such asheight, weight, sex and waist size is selectively input. The data thusinput is stored in the memory 15.

[0083] T3: After the percent body fat measurement starting switch 18 hasbeen turned ON thereby making the scale ready for percent body fatmeasurement, the fingers of both hands are brought into contact with theelectrodes 16 to measure the body impedance between the fingers of bothhands and the measurement data is stored in the memory 15.

[0084] T4: The percent body fat of the subject is calculated based onthe measurement data on the body impedance and the personal data storedin the memory 15, and the result of the calculation is stored in thememory 15. In the central processing unit 8, the BMI of the subject iscalculated based on the personal data while performing calculation ofthe abdominal visceral fat cross-sectional area (AV) of the subjectbased on the personal data and the data on the body impedance or percentbody fat. The results of the calculations are stored in the memory 15.The arithmetic expressions used for the above calculations have beenstored in the memory 15 beforehand and are called into the centralprocessing unit 8 when executing the arithmetic operations. As theexpression for obtaining abdominal visceral fat cross-sectional area(AV), the following regression equation (9) is used, which is obtainedby adding the auxiliary term of body impedance (Z) to the expression (1)used in the first embodiment:

AV=a ₂ ×W _(L) +b ₂ ×Z+d ₂  (9)

[0085] where W_(L) is waist size. The coefficients a₂, b₂ and constantd₂ of this expression are derived from a statistic technique based onthe correlation between the waist size and abdominal cross-section C/Tdata of a selected group of subjects.

[0086] Instead of the regression expression (9), the followingregression expression (10) may be used which is obtained by addingpercent body fat (FAT) as an auxiliary term.

AV=a ₃ ×W _(L) +C ₁×FAT+d ₃  (10)

[0087] The coefficients a₃, cl and constant d₃ of this expression arealso derived from a statistic technique based on the correlation betweenthe waist size and abdominal cross-section C/T data of a selected groupof subjects.

[0088] Further, the following expression (11) may be used which providesa higher coefficient of correlation (r=0.9 or more) for the C/T data:

AV=e ₁ ×W _(L) ² ×H _(L)×FAT+f ₁ ×W _(L) ² ×H _(L)×Age+d ₄  (11)

[0089] where HL is height and Age is age. The coefficients e₁, f₁ andthe constant d₄ are derived from a statistic technique based on thecorrelation between the abdominal cross-section C/T data and values I,II of a selected group of subjects. Herein, the value I is obtained bymultiplying the square of waist size by height and percent body fat,whereas the value II is obtained by multiplying the square of waist sizeby height and age.

[0090] Alternatively, the following equation (12) may be used:

AV=f ₂ ×W _(L) ² ×H _(L)×Age+g ₁×FAT+d ₅  (12)

[0091] The coefficients f₂, g₁ and constant d₅ of this equation arederived from a statistic technique based on the correlation between theabdominal cross-section C/T data, percent body fat, and a value of aselected group of subjects, the value being obtained by multiplying thesquare of waist size by height and age.

[0092] T5: The BMI, percent body fat and abdominal visceral fatcross-sectional area (AV), which have been calculated at step T4 andstored in the memory 15, are compared to their respective referencevalues used for the obesity assessment and the rank of obesity isdetermined to be stored in the memory 15. The reference values andequation used for the above comparative operations have been stored inthe memory 15 and called into the central processing unit 8 whenexecuting the arithmetic operations.

[0093] As the reference values for the assessment of obesity, BMI=25(for male and female), percent body fat (male: 20%, female: 30%), andabdominal visceral fat cross-sectional area (AV)=100 cm² (for male andfemale) are used. It should be noted that BMI is an indexinternationally used for assessment of obesity/emaciation, whereasabdominal visceral fat cross-sectional area (AV) represents the amountof distributed visceral fat and is used as an index to diagnosis ofobesity in the clinical site. Obesity is ranked according to the indicesBMI, percent body fat and AV. More specifically, BMI is classified asfollows: the range of 25 to 30 is rank I, the range of 30 to 35 is rankII and the range of 35 or more is rank III. Percent body fat isclassified as follows: for male, the range of 20 to 25% is rank I, therange of 25 to 30% is rank II and the range of more than 30% is rankIII, and for female, the range of 30 to 35% is rank I, the range of 35to 40% is rank II, and the range of more than 40% is rank III. Abdominalvisceral fat cross-sectional area (AV) is classified as follows: therange of 100 to 125 cm² is rank I, the range of 125 to 150 cm² is rankII and the range of 150 cm² or more is rank III.

[0094] The steps T6 to T24 to be performed onward are basically the sameas the steps S5 to S23 of the first embodiment except the followingpoints: The steps T13 and T16 differ from the steps S12 and S15 of thefirst embodiment in that a check is made at the steps T13 and T16whether or not percent body fat (FAT) exceeds 20% (in the case of male)or 30% (in the case of female). The step T24 differs from the step S23of the first embodiment in that the display contents of the display unit9 at the step T24 includes percent body fat as an index to theassessment of obesity. In view of this, a detailed description of thesteps T6 to T24 will be omitted herein.

[0095] In the foregoing embodiments, the abdominal visceral fatcross-sectional area of the subject is obtained from the input personaldata of the subject (height, weight, age, sex, waist size etc.), usingan arithmetic expression stored beforehand. Herein, waist size may beestimated from the input data on the height, weight and age of thesubject. An example of the equation used for this estimation is thefollowing equation (13):

W_(L) =m ₁ ×W/H _(L) ² ×n ₁×Age+I ₁  (13)

[0096] where W is weight, H_(L) is height, and Age is age.

[0097] Based on the waist size which has been obtained from the abovearithmetic operation and the personal data (height, weight, age, sexetc.) of the subject, the abdominal visceral fat cross-sectional area ofthe subject may be calculated with the arithmetic expression used in theforegoing embodiments. This saves the trouble of measurement andinputting of waist size, so that visceral fat can be more readilyobtained.

What is claimed is:
 1. A visceral fat scale equipped with asphygmomanometer, wherein after exerting pressure to an artery of asubject by inflation of a cuff, a pulse wave signal is detected in thecourse of gradual cuff deflation and blood pressure is obtained based onthe detected pulse wave signal, the visceral fat scale comprising: aninput device for inputting personal data of the subject; an arithmeticoperation unit for calculating the amount of visceral fat of the subjectbased on the data input by the input device; and a display unit fordisplaying a result of the calculation performed by the arithmeticoperation unit.
 2. The visceral fat scale equipped with asphygmomanometer according to claim 1, wherein the personal data inputby the input device includes the height, weight and waist size of thesubject and wherein the arithmetic operation unit calculates the BMI ofthe subject in addition to the amount of visceral fat of the subjectbased on the data input by the input device.
 3. The visceral fat scaleequipped with a sphygmomanometer according to claim 2, wherein thedisplay unit displays the respective ranks of the visceral fat amountand BMI of the subject, each of said indices having a plurality ofranks.
 4. The visceral fat scale equipped with a sphygmomanometeraccording to claim 2 or 3, wherein the arithmetic operation unit makesan assessment of obesity by comparing the amount of visceral fat and BMIof the subject with their respective reference values for assessmentwhich have been input beforehand, and wherein the display unit displaysa result of the assessment of obesity.
 5. The visceral fat scaleequipped with a sphygmomanometer according to claim 1, wherein thedisplay unit displays blood pressure values and the amount of visceralfat at the same time.
 6. The visceral fat scale equipped with asphygmomanometer according to claim 1, wherein the arithmetic operationunit calculates the amount of change from a previous measurement resultand the ratio of the present measurement result to the previousmeasurement result for the blood pressure values and visceral fat amountof the subject, and wherein the display unit displays a result of thecalculation.
 7. The visceral fat scale equipped with a sphygmomanometeraccording to claim 1, wherein the amount of visceral fat is thecross-sectional area of abdominal visceral fat of the subject.
 8. Thevisceral fat scale equipped with a sphygmomanometer according to claim7, wherein a target inflation value for the cuff is determined by asystolic blood pressure estimated based on a pulse wave generated duringcuff inflation and by the cross-sectional area of abdominal visceralfat.
 9. The visceral fat scale equipped with a sphygmomanometeraccording to claim 7, wherein a target inflation value for the cuff isdetermined by a systolic blood pressure estimated based on a pulse wavegenerated during cuff inflation and by a result of the assessment ofobesity.
 10. A visceral fat scale equipped with a sphygmomanometer,wherein after exerting pressure to an artery of a subject by inflationof a cuff, a pulse wave signal is detected in the course of gradual cuffdeflation and blood pressure is obtained based on the detected pulsewave signal, the visceral fat scale comprising: an input device forinputting personal data including the height, weight and waist size ofthe subject; electrodes for current application and electrodes formeasurement which are brought into contact with part of the body of thesubject; a body impedance measuring unit for measuring the bodyimpedance of the subject based on a signal from the measurementelectrodes; an arithmetic operation unit for calculating at least any ofthe BMI, percent body fat and visceral fat amount of the subject basedon data input by the body impedance measuring unit and data input by theinput device; and a display unit for displaying a result of thecalculation performed by the arithmetic operation unit.
 11. The visceralfat scale equipped with a sphygmomanometer according to claim 10,wherein the display unit displays the rank of any of the BMI, percentbody fat and visceral fat amount of the subject, each of said indiceshaving a plurality of ranks.
 12. The visceral fat scale equipped with asphygmomanometer according to claim 10 or 11, wherein the arithmeticoperation unit makes an assessment of obesity by comparing any of theBMI, percent body fat and visceral fat amount of the subject with theirrespective reference values for assessment which have been inputbeforehand, and wherein the display unit displays a result of theassessment of obesity.
 13. The visceral fat scale equipped with asphygmomanometer according to claim 10, wherein the display unitdisplays blood pressure values and the amount of visceral fat at thesame time.
 14. The visceral fat scale equipped with a sphygmomanometeraccording to claim 10, wherein the arithmetic operation unit calculatesthe amount of change from a previous measurement result and the ratio ofthe present measurement result to the previous measurement result forthe blood pressure values and visceral fat amount of the subject, andwherein the display unit displays a result of the calculation.
 15. Thevisceral fat scale equipped with a sphygmomanometer according to claim10, wherein the amount of visceral fat is the cross-sectional area ofabdominal visceral fat of the subject.
 16. The visceral fat scaleequipped with a sphygmomanometer according to claim 15, wherein a targetinflation value for the cuff is determined by a systolic blood pressureestimated based on a pulse wave generated during cuff inflation and bythe cross-sectional area of abdominal visceral fat.
 17. The visceral fatscale equipped with a sphygmomanometer according to claim 15, wherein atarget inflation value for the cuff is determined by a systolic bloodpressure estimated based on a pulse wave generated during cuff inflationand by a result of the assessment of obesity.